/*! KeyTable 1.2.1
 * ©2010-2014 SpryMedia Ltd - datatables.net/license
 */

/**
 * @summary     KeyTable
 * @description Spreadsheet like keyboard navigation for DataTables
 * @version     1.2.1
 * @file        dataTables.keyTable.js
 * @author      SpryMedia Ltd (www.sprymedia.co.uk)
 * @contact     www.sprymedia.co.uk/contact
 * @copyright   Copyright 2009-2014 SpryMedia Ltd.
 *
 * This source file is free software, available under the following license:
 *   MIT license - http://datatables.net/license/mit
 *
 * This source file is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the license files for details.
 *
 * For details please refer to: http://www.datatables.net
 */

// Global scope for KeyTable for backwards compatibility. Will be removed in 1.3
var KeyTable;


(function (window, document, undefined) {


    var factory = function ($, DataTable) {
        "use strict";

        KeyTable = function (oInit)
        {
            /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
             * API parameters
             * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

            /*
             * Variable: block
             * Purpose:  Flag whether or not KeyTable events should be processed
             * Scope:    KeyTable - public
             */
            this.block = false;

            /*
             * Variable: event
             * Purpose:  Container for all event application methods
             * Scope:    KeyTable - public
             * Notes:    This object contains all the public methods for adding and removing events - these
             *           are dynamically added later on
             */
            this.event = {
                "remove": {}
            };


            /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
             * API methods
             * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

            /*
             * Function: fnGetCurrentPosition
             * Purpose:  Get the currently focused cell's position
             * Returns:  array int: [ x, y ]
             * Inputs:   void
             */
            this.fnGetCurrentPosition = function ()
            {
                return [_iOldX, _iOldY];
            };


            /*
             * Function: fnGetCurrentData
             * Purpose:  Get the currently focused cell's data (innerHTML)
             * Returns:  string: - data requested
             * Inputs:   void
             */
            this.fnGetCurrentData = function ()
            {
                return _nOldFocus.innerHTML;
            };


            /*
             * Function: fnGetCurrentTD
             * Purpose:  Get the currently focused cell
             * Returns:  node: - focused element
             * Inputs:   void
             */
            this.fnGetCurrentTD = function ()
            {
                return _nOldFocus;
            };


            /*
             * Function: fnSetPosition
             * Purpose:  Set the position of the focused cell
             * Returns:  -
             * Inputs:   int:x - x coordinate
             *           int:y - y coordinate
             * Notes:    Thanks to Rohan Daxini for the basis of this function
             */
            this.fnSetPosition = function (x, y)
            {
                if (typeof x == 'object' && x.nodeName)
                {
                    _fnSetFocus(x);
                } else
                {
                    _fnSetFocus(_fnCellFromCoords(x, y));
                }
            };


            /*
             * Function: fnBlur
             * Purpose:  Blur the current focus
             * Returns:  -
             * Inputs:   -
             */
            this.fnBlur = function ()
            {
                _fnBlur();
            };


            /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
             * Private parameters
             * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

            /*
             * Variable: _nBody
             * Purpose:  Body node of the table - cached for renference
             * Scope:    KeyTable - private
             */
            var _nBody = null;

            /*
             * Variable: 
             * Purpose:  
             * Scope:    KeyTable - private
             */
            var _nOldFocus = null;

            /*
             * Variable: _iOldX and _iOldY
             * Purpose:  X and Y coords of the old elemet that was focused on
             * Scope:    KeyTable - private
             */
            var _iOldX = null;
            var _iOldY = null;

            /*
             * Variable: _that
             * Purpose:  Scope saving for 'this' after a jQuery event
             * Scope:    KeyTable - private
             */
            var _that = null;

            /*
             * Variable: sFocusClass
             * Purpose:  Class that should be used for focusing on a cell
             * Scope:    KeyTable - private
             */
            var _sFocusClass = "focus";

            /*
             * Variable: _bKeyCapture
             * Purpose:  Flag for should KeyTable capture key events or not
             * Scope:    KeyTable - private
             */
            var _bKeyCapture = false;

            /*
             * Variable: _oaoEvents
             * Purpose:  Event cache object, one array for each supported event for speed of searching
             * Scope:    KeyTable - private
             */
            var _oaoEvents = {
                "action": [],
                "esc": [],
                "focus": [],
                "blur": []
            };

            /*
             * Variable: _oDatatable
             * Purpose:  DataTables settings object for if we are actually using a 
             *           DataTables table
             * Scope:    KeyTable - private
             */
            var _oDatatable = null;

            var _bForm;
            var _nInput;
            var _bInputFocused = false;


            /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
             * Private methods
             * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

            /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
             * Key table events
             */

            /*
             * Function: _fnEventAddTemplate
             * Purpose:  Create a function (with closure for sKey) event addition API
             * Returns:  function: - template function
             * Inputs:   string:sKey - type of event to detect
             */
            function _fnEventAddTemplate(sKey)
            {
                /*
                 * Function: -
                 * Purpose:  API function for adding event to cache
                 * Returns:  -
                 * Inputs:   1. node:x - target node to add event for
                 *           2. function:y - callback function to apply
                 *         or
                 *           1. int:x - x coord. of target cell (can be null for live events)
                 *           2. int:y - y coord. of target cell (can be null for live events)
                 *           3. function:z - callback function to apply
                 * Notes:    This function is (interally) overloaded (in as much as javascript allows for
                 *           that) - the target cell can be given by either node or coords.
                 */
                return function (x, y, z) {
                    if ((x === null || typeof x == "number") &&
                            (y === null || typeof y == "number") &&
                            typeof z == "function")
                    {
                        _fnEventAdd(sKey, x, y, z);
                    } else if (typeof x == "object" && typeof y == "function")
                    {
                        var aCoords = _fnCoordsFromCell(x);
                        _fnEventAdd(sKey, aCoords[0], aCoords[1], y);
                    } else
                    {
                        alert("Unhandable event type was added: x" + x + "  y:" + y + "  z:" + z);
                    }
                };
            }


            /*
             * Function: _fnEventRemoveTemplate
             * Purpose:  Create a function (with closure for sKey) event removal API
             * Returns:  function: - template function
             * Inputs:   string:sKey - type of event to detect
             */
            function _fnEventRemoveTemplate(sKey)
            {
                /*
                 * Function: -
                 * Purpose:  API function for removing event from cache
                 * Returns:  int: - number of events removed
                 * Inputs:   1. node:x - target node to remove event from
                 *           2. function:y - callback function to apply
                 *         or
                 *           1. int:x - x coord. of target cell (can be null for live events)
                 *           2. int:y - y coord. of target cell (can be null for live events)
                 *           3. function:z - callback function to remove - optional
                 * Notes:    This function is (interally) overloaded (in as much as javascript allows for
                 *           that) - the target cell can be given by either node or coords and the function
                 *           to remove is optional
                 */
                return function (x, y, z) {
                    if ((x === null || typeof arguments[0] == "number") &&
                            (y === null || typeof arguments[1] == "number"))
                    {
                        if (typeof arguments[2] == "function")
                        {
                            _fnEventRemove(sKey, x, y, z);
                        } else
                        {
                            _fnEventRemove(sKey, x, y);
                        }
                    } else if (typeof arguments[0] == "object")
                    {
                        var aCoords = _fnCoordsFromCell(x);
                        if (typeof arguments[1] == "function")
                        {
                            _fnEventRemove(sKey, aCoords[0], aCoords[1], y);
                        } else
                        {
                            _fnEventRemove(sKey, aCoords[0], aCoords[1]);
                        }
                    } else
                    {
                        alert("Unhandable event type was removed: x" + x + "  y:" + y + "  z:" + z);
                    }
                };
            }

            /* Use the template functions to add the event API functions */
            for (var sKey in _oaoEvents)
            {
                if (sKey)
                {
                    this.event[sKey] = _fnEventAddTemplate(sKey);
                    this.event.remove[sKey] = _fnEventRemoveTemplate(sKey);
                }
            }


            /*
             * Function: _fnEventAdd
             * Purpose:  Add an event to the internal cache
             * Returns:  -
             * Inputs:   string:sType - type of event to add, given by the available elements in _oaoEvents
             *           int:x - x-coords to add event to - can be null for "blanket" event
             *           int:y - y-coords to add event to - can be null for "blanket" event
             *           function:fn - callback function for when triggered
             */
            function _fnEventAdd(sType, x, y, fn)
            {
                _oaoEvents[sType].push({
                    "x": x,
                    "y": y,
                    "fn": fn
                });
            }


            /*
             * Function: _fnEventRemove
             * Purpose:  Remove an event from the event cache
             * Returns:  int: - number of matching events removed
             * Inputs:   string:sType - type of event to look for
             *           node:nTarget - target table cell
             *           function:fn - optional - remove this function. If not given all handlers of this
             *             type will be removed
             */
            function _fnEventRemove(sType, x, y, fn)
            {
                var iCorrector = 0;

                for (var i = 0, iLen = _oaoEvents[sType].length; i < iLen - iCorrector; i++)
                {
                    if (typeof fn != 'undefined')
                    {
                        if (_oaoEvents[sType][i - iCorrector].x == x &&
                                _oaoEvents[sType][i - iCorrector].y == y &&
                                _oaoEvents[sType][i - iCorrector].fn == fn)
                        {
                            _oaoEvents[sType].splice(i - iCorrector, 1);
                            iCorrector++;
                        }
                    } else
                    {
                        if (_oaoEvents[sType][i - iCorrector].x == x &&
                                _oaoEvents[sType][i - iCorrector].y == y)
                        {
                            _oaoEvents[sType].splice(i, 1);
                            return 1;
                        }
                    }
                }
                return iCorrector;
            }


            /*
             * Function: _fnEventFire
             * Purpose:  Look thought the events cache and fire off the event of interest
             * Returns:  int:iFired - number of events fired
             * Inputs:   string:sType - type of event to look for
             *           int:x - x coord of cell
             *           int:y - y coord of  ell
             * Notes:    It might be more efficient to return after the first event has been tirggered,
             *           but that would mean that only one function of a particular type can be
             *           subscribed to a particular node.
             */
            function _fnEventFire(sType, x, y)
            {
                var iFired = 0;
                var aEvents = _oaoEvents[sType];
                for (var i = 0; i < aEvents.length; i++)
                {
                    if ((aEvents[i].x == x && aEvents[i].y == y) ||
                            (aEvents[i].x === null && aEvents[i].y == y) ||
                            (aEvents[i].x == x && aEvents[i].y === null) ||
                            (aEvents[i].x === null && aEvents[i].y === null)
                            )
                    {
                        aEvents[i].fn(_fnCellFromCoords(x, y), x, y);
                        iFired++;
                    }
                }
                return iFired;
            }



            /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
             * Focus functions
             */

            /*
             * Function: _fnSetFocus
             * Purpose:  Set focus on a node, and remove from an old node if needed
             * Returns:  -
             * Inputs:   node:nTarget - node we want to focus on
             *           bool:bAutoScroll - optional - should we scroll the view port to the display
             */
            function _fnSetFocus(nTarget, bAutoScroll)
            {
                /* If node already has focus, just ignore this call */
                if (_nOldFocus == nTarget)
                {
                    return;
                }

                if (typeof bAutoScroll == 'undefined')
                {
                    bAutoScroll = true;
                }

                /* Remove old focus (with blur event if needed) */
                if (_nOldFocus !== null)
                {
                    _fnRemoveFocus(_nOldFocus);
                }

                /* Add the new class to highlight the focused cell */
                $(nTarget).addClass(_sFocusClass);
                $(nTarget).parent().addClass(_sFocusClass);

                /* If it's a DataTable then we need to jump the paging to the relevant page */
                var oSettings;
                if (_oDatatable)
                {
                    oSettings = _oDatatable;
                    var iRow = _fnFindDtCell(nTarget)[1];
                    var bKeyCaptureCache = _bKeyCapture;

                    /* Page forwards */
                    while (iRow >= oSettings.fnDisplayEnd())
                    {
                        if (oSettings._iDisplayLength >= 0)
                        {
                            /* Make sure we are not over running the display array */
                            if (oSettings._iDisplayStart + oSettings._iDisplayLength < oSettings.fnRecordsDisplay())
                            {
                                oSettings._iDisplayStart += oSettings._iDisplayLength;
                            }
                        } else
                        {
                            oSettings._iDisplayStart = 0;
                        }
                        _oDatatable.oApi._fnCalculateEnd(oSettings);
                    }

                    /* Page backwards */
                    while (iRow < oSettings._iDisplayStart)
                    {
                        oSettings._iDisplayStart = oSettings._iDisplayLength >= 0 ?
                                oSettings._iDisplayStart - oSettings._iDisplayLength :
                                0;

                        if (oSettings._iDisplayStart < 0)
                        {
                            oSettings._iDisplayStart = 0;
                        }
                        _oDatatable.oApi._fnCalculateEnd(oSettings);
                    }

                    /* Re-draw the table */
                    _oDatatable.oApi._fnDraw(oSettings);

                    /* Restore the key capture */
                    _bKeyCapture = bKeyCaptureCache;
                }

                /* Cache the information that we are interested in */
                var aNewPos = _fnCoordsFromCell(nTarget);
                _nOldFocus = nTarget;
                _iOldX = aNewPos[0];
                _iOldY = aNewPos[1];

                var iViewportHeight, iViewportWidth, iScrollTop, iScrollLeft, iHeight, iWidth, aiPos;
                if (bAutoScroll)
                {
                    /* Scroll the viewport such that the new cell is fully visible in the rendered window */
                    iViewportHeight = $(window).height();
                    iViewportWidth = $(window).width();
                    iScrollTop = $(document).scrollTop();
                    iScrollLeft = $(document).scrollLeft();
                    iHeight = nTarget.offsetHeight;
                    iWidth = nTarget.offsetWidth;
                    aiPos = _fnGetPos(nTarget);

                    /* Take account of scrolling in DataTables 1.7 - remove scrolling since that would add to
                     * the positioning calculation
                     */
                    if (_oDatatable && typeof oSettings.oScroll != 'undefined' &&
                            (oSettings.oScroll.sX !== "" || oSettings.oScroll.sY !== ""))
                    {
                        aiPos[1] -= $(oSettings.nTable.parentNode).scrollTop();
                        aiPos[0] -= $(oSettings.nTable.parentNode).scrollLeft();
                    }

                    /* Correct viewport positioning for vertical scrolling */
                    if (aiPos[1] + iHeight > iScrollTop + iViewportHeight)
                    {
                        /* Displayed element if off the bottom of the viewport */
                        _fnSetScrollTop(aiPos[1] + iHeight - iViewportHeight);
                    } else if (aiPos[1] < iScrollTop)
                    {
                        /* Displayed element if off the top of the viewport */
                        _fnSetScrollTop(aiPos[1]);
                    }

                    /* Correct viewport positioning for horizontal scrolling */
                    if (aiPos[0] + iWidth > iScrollLeft + iViewportWidth)
                    {
                        /* Displayed element is off the bottom of the viewport */
                        _fnSetScrollLeft(aiPos[0] + iWidth - iViewportWidth);
                    } else if (aiPos[0] < iScrollLeft)
                    {
                        /* Displayed element if off the Left of the viewport */
                        _fnSetScrollLeft(aiPos[0]);
                    }
                }

                /* Take account of scrolling in DataTables 1.7 */
                if (_oDatatable && typeof oSettings.oScroll != 'undefined' &&
                        (oSettings.oScroll.sX !== "" || oSettings.oScroll.sY !== ""))
                {
                    var dtScrollBody = oSettings.nTable.parentNode;
                    iViewportHeight = dtScrollBody.clientHeight;
                    iViewportWidth = dtScrollBody.clientWidth;
                    iScrollTop = dtScrollBody.scrollTop;
                    iScrollLeft = dtScrollBody.scrollLeft;
                    iHeight = nTarget.offsetHeight;
                    iWidth = nTarget.offsetWidth;

                    /* Correct for vertical scrolling */
                    if (nTarget.offsetTop + iHeight > iViewportHeight + iScrollTop)
                    {
                        dtScrollBody.scrollTop = (nTarget.offsetTop + iHeight) - iViewportHeight;
                    } else if (nTarget.offsetTop < iScrollTop)
                    {
                        dtScrollBody.scrollTop = nTarget.offsetTop;
                    }

                    /* Correct for horizontal scrolling */
                    if (nTarget.offsetLeft + iWidth > iViewportWidth + iScrollLeft)
                    {
                        dtScrollBody.scrollLeft = (nTarget.offsetLeft + iWidth) - iViewportWidth;
                    } else if (nTarget.offsetLeft < iScrollLeft)
                    {
                        dtScrollBody.scrollLeft = nTarget.offsetLeft;
                    }
                }

                /* Focused - so we want to capture the keys */
                _fnCaptureKeys();

                /* Fire of the focus event if there is one */
                _fnEventFire("focus", _iOldX, _iOldY);
            }


            /*
             * Function: _fnBlur
             * Purpose:  Blur focus from the whole table
             * Returns:  -
             * Inputs:   -
             */
            function _fnBlur()
            {
                _fnRemoveFocus(_nOldFocus);
                _iOldX = null;
                _iOldY = null;
                _nOldFocus = null;
                _fnReleaseKeys();
            }


            /*
             * Function: _fnRemoveFocus
             * Purpose:  Remove focus from a cell and fire any blur events which are attached
             * Returns:  -
             * Inputs:   node:nTarget - cell of interest
             */
            function _fnRemoveFocus(nTarget)
            {
                $(nTarget).removeClass(_sFocusClass);
                $(nTarget).parent().removeClass(_sFocusClass);
                _fnEventFire("blur", _iOldX, _iOldY);
            }


            /*
             * Function: _fnClick
             * Purpose:  Focus on the element that has been clicked on by the user
             * Returns:  -
             * Inputs:   event:e - click event
             */
            function _fnClick(e)
            {
                var nTarget = this;
                while (nTarget.nodeName != "TD")
                {
                    nTarget = nTarget.parentNode;
                }

                _fnSetFocus(nTarget);
                _fnCaptureKeys();
            }



            /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
             * Key events
             */

            /*
             * Function: _fnKey
             * Purpose:  Deal with a key events, be it moving the focus or return etc.
             * Returns:  bool: - allow browser default action
             * Inputs:   event:e - key event
             */
            function _fnKey(e)
            {
                /* If user or system has blocked KeyTable from doing anything, just ignore this event */
                if (_that.block || !_bKeyCapture)
                {
                    return true;
                }

                /* If a modifier key is pressed (exapct shift), ignore the event */
                if (e.metaKey || e.altKey || e.ctrlKey)
                {
                    return true;
                }
                var
                        x, y,
                        iTableWidth = _nBody.getElementsByTagName('tr')[0].getElementsByTagName('td').length,
                        iTableHeight;

                /* Get table height and width - done here so as to be dynamic (if table is updated) */
                if (_oDatatable)
                {
                    /* 
                     * Locate the current node in the DataTable overriding the old positions - the reason for
                     * is is that there might have been some DataTables interaction between the last focus and
                     * now
                     */
                    iTableHeight = _oDatatable.aiDisplay.length;

                    var aDtPos = _fnFindDtCell(_nOldFocus);
                    if (aDtPos === null)
                    {
                        /* If the table has been updated such that the focused cell can't be seen - do nothing */
                        return;
                    }
                    _iOldX = aDtPos[ 0 ];
                    _iOldY = aDtPos[ 1 ];
                } else
                {
                    iTableHeight = _nBody.getElementsByTagName('tr').length;
                }

                /* Capture shift+tab to match the left arrow key */
                var iKey = (e.keyCode == 9 && e.shiftKey) ? -1 : e.keyCode;

                switch (iKey)
                {
                    case 13: /* return */
                        e.preventDefault();
                        e.stopPropagation();
                        _fnEventFire("action", _iOldX, _iOldY);
                        return true;

                    case 27: /* esc */
                        if (!_fnEventFire("esc", _iOldX, _iOldY))
                        {
                            /* Only lose focus if there isn't an escape handler on the cell */
                            _fnBlur();
                            return;
                        }
                        x = _iOldX;
                        y = _iOldY;
                        break;

                    case - 1:
                    case 37: /* left arrow */
                        if (_iOldX > 0) {
                            x = _iOldX - 1;
                            y = _iOldY;
                        } else if (_iOldY > 0) {
                            x = iTableWidth - 1;
                            y = _iOldY - 1;
                        } else {
                            /* at start of table */
                            if (iKey == -1 && _bForm)
                            {
                                /* If we are in a form, return focus to the 'input' element such that tabbing will
                                 * follow correctly in the browser
                                 */
                                _bInputFocused = true;
                                _nInput.focus();

                                /* This timeout is a little nasty - but IE appears to have some asyhnc behaviour for 
                                 * focus
                                 */
                                setTimeout(function () {
                                    _bInputFocused = false;
                                }, 0);
                                _bKeyCapture = false;
                                _fnBlur();
                                return true;
                            } else
                            {
                                return false;
                            }
                        }
                        break;

                    case 38: /* up arrow */
                        if (_iOldY > 0) {
                            x = _iOldX;
                            y = _iOldY - 1;
                        } else {
                            return false;
                        }
                        break;

                    case 36: /* home */
                        x = _iOldX;
                        y = 0;
                        break;

                    case 33: /* page up */
                        x = _iOldX;
                        y = _iOldY - 10;
                        if (y < 0) {
                            y = 0;
                        }
                        break;

                    case 9: /* tab */
                    case 39: /* right arrow */
                        if (_iOldX < iTableWidth - 1) {
                            x = _iOldX + 1;
                            y = _iOldY;
                        } else if (_iOldY < iTableHeight - 1) {
                            x = 0;
                            y = _iOldY + 1;
                        } else {
                            /* at end of table */
                            if (iKey == 9 && _bForm)
                            {
                                /* If we are in a form, return focus to the 'input' element such that tabbing will
                                 * follow correctly in the browser
                                 */
                                _bInputFocused = true;
                                _nInput.focus();

                                /* This timeout is a little nasty - but IE appears to have some asyhnc behaviour for 
                                 * focus
                                 */
                                setTimeout(function () {
                                    _bInputFocused = false;
                                }, 0);
                                _bKeyCapture = false;
                                _fnBlur();
                                return true;
                            } else
                            {
                                return false;
                            }
                        }
                        break;

                    case 40: /* down arrow */
                        if (_iOldY < iTableHeight - 1) {
                            x = _iOldX;
                            y = _iOldY + 1;
                        } else {
                            return false;
                        }
                        break;

                    case 35: /* end */
                        x = _iOldX;
                        y = iTableHeight - 1;
                        break;

                    case 34: /* page down */
                        x = _iOldX;
                        y = _iOldY + 10;
                        if (y > iTableHeight - 1) {
                            y = iTableHeight - 1;
                        }
                        break;

                    default: /* Nothing we are interested in */
                        return true;
                }

                _fnSetFocus(_fnCellFromCoords(x, y));
                return false;
            }


            /*
             * Function: _fnCaptureKeys
             * Purpose:  Start capturing key events for this table
             * Returns:  -
             * Inputs:   -
             */
            function _fnCaptureKeys( )
            {
                if (!_bKeyCapture)
                {
                    _bKeyCapture = true;
                }
            }


            /*
             * Function: _fnReleaseKeys
             * Purpose:  Stop capturing key events for this table
             * Returns:  -
             * Inputs:   -
             */
            function _fnReleaseKeys( )
            {
                _bKeyCapture = false;
            }



            /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
             * Support functions
             */

            /*
             * Function: _fnCellFromCoords
             * Purpose:  Calulate the target TD cell from x and y coordinates
             * Returns:  node: - TD target
             * Inputs:   int:x - x coordinate
             *           int:y - y coordinate
             */
            function _fnCellFromCoords(x, y)
            {
                if (_oDatatable)
                {
                    if (typeof _oDatatable.aoData[ _oDatatable.aiDisplay[ y ] ] != 'undefined')
                    {
                        return _oDatatable.aoData[ _oDatatable.aiDisplay[ y ] ].nTr.getElementsByTagName('td')[x];
                    } else
                    {
                        return null;
                    }
                } else
                {
                    return $('tr:eq(' + y + ')>td:eq(' + x + ')', _nBody)[0];
                }
            }


            /*
             * Function: _fnCoordsFromCell
             * Purpose:  Calculate the x and y position in a table from a TD cell
             * Returns:  array[2] int: [x, y]
             * Inputs:   node:n - TD cell of interest
             * Notes:    Not actually interested in this for DataTables since it might go out of date
             */
            function _fnCoordsFromCell(n)
            {
                if (_oDatatable)
                {
                    return [
                        $('td', n.parentNode).index(n),
                        $('tr', n.parentNode.parentNode).index(n.parentNode) + _oDatatable._iDisplayStart
                    ];
                } else
                {
                    return [
                        $('td', n.parentNode).index(n),
                        $('tr', n.parentNode.parentNode).index(n.parentNode)
                    ];
                }
            }


            /*
             * Function: _fnSetScrollTop
             * Purpose:  Set the vertical scrolling position
             * Returns:  -
             * Inputs:   int:iPos - scrolltop
             * Notes:    This is so nasty, but without browser detection you can't tell which you should set
             *           So on browsers that support both, the scroll top will be set twice. I can live with
             *           that :-)
             */
            function _fnSetScrollTop(iPos)
            {
                document.documentElement.scrollTop = iPos;
                document.body.scrollTop = iPos;
            }


            /*
             * Function: _fnSetScrollLeft
             * Purpose:  Set the horizontal scrolling position
             * Returns:  -
             * Inputs:   int:iPos - scrollleft
             */
            function _fnSetScrollLeft(iPos)
            {
                document.documentElement.scrollLeft = iPos;
                document.body.scrollLeft = iPos;
            }


            /*
             * Function: _fnGetPos
             * Purpose:  Get the position of an object on the rendered page
             * Returns:  array[2] int: [left, right]
             * Inputs:   node:obj - element of interest
             */
            function _fnGetPos(obj)
            {
                var iLeft = 0;
                var iTop = 0;

                if (obj.offsetParent)
                {
                    iLeft = obj.offsetLeft;
                    iTop = obj.offsetTop;
                    obj = obj.offsetParent;
                    while (obj)
                    {
                        iLeft += obj.offsetLeft;
                        iTop += obj.offsetTop;
                        obj = obj.offsetParent;
                    }
                }
                return [iLeft, iTop];
            }


            /*
             * Function: _fnFindDtCell
             * Purpose:  Get the coords. of a cell from the DataTables internal information
             * Returns:  array[2] int: [x, y] coords. or null if not found
             * Inputs:   node:nTarget - the node of interest
             */
            function _fnFindDtCell(nTarget)
            {
                for (var i = 0, iLen = _oDatatable.aiDisplay.length; i < iLen; i++)
                {
                    var nTr = _oDatatable.aoData[ _oDatatable.aiDisplay[i] ].nTr;
                    var nTds = nTr.getElementsByTagName('td');
                    for (var j = 0, jLen = nTds.length; j < jLen; j++)
                    {
                        if (nTds[j] == nTarget)
                        {
                            return [j, i];
                        }
                    }
                }
                return null;
            }



            /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
             * Initialisation
             */

            /*
             * Function: _fnInit
             * Purpose:  Initialise the KeyTable
             * Returns:  -
             * Inputs:   object:oInit - optional - Initalisation object with the following parameters:
             *   array[2] int:focus - x and y coordinates of the initial target
             *     or
             *     node:focus - the node to set initial focus on
             *   node:table - the table to use, if not given, first table with class 'KeyTable' will be used
             *   string:focusClass - focusing class to give to table elements
             *           object:that - focus
             *   bool:initScroll - scroll the view port on load, default true
             *   int:tabIndex - the tab index to give the hidden input element
             */
            function _fnInit(table, datatable, oInit, that)
            {
                /* Save scope */
                _that = that;

                /* Capture undefined initialisation and apply the defaults */
                if (typeof oInit == 'undefined') {
                    oInit = {};
                }

                if (typeof oInit.focus == 'undefined') {
                    oInit.focus = [0, 0];
                }

                oInit.table = table;
                $(oInit.table).addClass('KeyTable');

                if (typeof oInit.focusClass != 'undefined') {
                    _sFocusClass = oInit.focusClass;
                }

                if (typeof datatable != 'undefined') {
                    _oDatatable = datatable;
                }

                if (typeof oInit.initScroll == 'undefined') {
                    oInit.initScroll = true;
                }

                if (typeof oInit.form == 'undefined') {
                    oInit.form = false;
                }
                _bForm = oInit.form;

                /* Cache the tbody node of interest */
                _nBody = oInit.table.getElementsByTagName('tbody')[0];

                /* If the table is inside a form, then we need a hidden input box which can be used by the
                 * browser to catch the browser tabbing for our table
                 */
                if (_bForm)
                {
                    var nDiv = document.createElement('div');
                    _nInput = document.createElement('input');
                    nDiv.style.height = "1px"; /* Opera requires a little something */
                    nDiv.style.width = "0px";
                    nDiv.style.overflow = "hidden";
                    if (typeof oInit.tabIndex != 'undefined')
                    {
                        _nInput.tabIndex = oInit.tabIndex;
                    }
                    nDiv.appendChild(_nInput);
                    oInit.table.parentNode.insertBefore(nDiv, oInit.table.nextSibling);

                    $(_nInput).focus(function () {
                        /* See if we want to 'tab into' the table or out */
                        if (!_bInputFocused)
                        {
                            _bKeyCapture = true;
                            _bInputFocused = false;
                            if (typeof oInit.focus.nodeName != "undefined")
                            {
                                _fnSetFocus(oInit.focus, oInit.initScroll);
                            } else
                            {
                                _fnSetFocus(_fnCellFromCoords(oInit.focus[0], oInit.focus[1]), oInit.initScroll);
                            }

                            /* Need to interup the thread for this to work */
                            setTimeout(function () {
                                _nInput.blur();
                            }, 0);
                        }
                    });
                    _bKeyCapture = false;
                } else
                {
                    /* Set the initial focus on the table */
                    if (typeof oInit.focus.nodeName != "undefined")
                    {
                        _fnSetFocus(oInit.focus, oInit.initScroll);
                    } else
                    {
                        _fnSetFocus(_fnCellFromCoords(oInit.focus[0], oInit.focus[1]), oInit.initScroll);
                    }
                    _fnCaptureKeys();
                }

                /* Add event listeners */
                $(document).bind("keydown", _fnKey);

                if (_oDatatable)
                {
                    $(_oDatatable.nTable).on('click', 'td', _fnClick);
                } else
                {
                    $(_nBody).on('click', 'td', _fnClick);
                }

                /* Loose table focus when click outside the table */
                $(document).click(function (e) {
                    var nTarget = e.target;
                    var bTableClick = false;
                    while (nTarget)
                    {
                        if (nTarget == oInit.table)
                        {
                            bTableClick = true;
                            break;
                        }
                        nTarget = nTarget.parentNode;
                    }
                    if (!bTableClick)
                    {
                        _fnBlur();
                    }
                });
            }

            var table, datatable;

            if (oInit === undefined) {
                table = $('table.KeyTable')[0];
                datatable = null;
            } else if ($.isPlainObject(oInit)) {
                table = oInit.table;
                datatable = oInit.datatable;
            } else {
                datatable = new $.fn.dataTable.Api(oInit).settings()[0];
                table = datatable.nTable;
            }
            /* Initialise our new object */
            _fnInit(table, datatable, oInit, this);
        };


        KeyTable.version = "1.2.1";


        $.fn.dataTable.KeyTable = KeyTable;
        $.fn.DataTable.KeyTable = KeyTable;


        return KeyTable;
    }; // /factory


// Define as an AMD module if possible
    if (typeof define === 'function' && define.amd) {
        define(['jquery', 'datatables'], factory);
    } else if (typeof exports === 'object') {
        // Node/CommonJS
        factory(require('jquery'), require('datatables'));
    } else if (jQuery && !jQuery.fn.dataTable.KeyTable) {
        // Otherwise simply initialise as normal, stopping multiple evaluation
        factory(jQuery, jQuery.fn.dataTable);
    }


})(window, document);
